The present invention relates to an apparatus for controlling a flow of granular material, such as shale particles, hot spent shale particles, coal particles, fly ash, or catalyst particles, out of an outlet such as an outlet of a container or a reaction vessel of a catalytic unit, for example a catalytic cracking unit, or through a conduit.
It is an object of the present invention to provide a simple and cheap apparatus which is suitable for controlling the flow out of a large outlet having for example a diameter larger than 0.1 m and suitably larger than 0.5 m, or through a conduit having such a large diameter.